A network topology used in a data center is a spine-leaf architecture, where multiple leaf network elements provide network access for servers that are in multiple server racks. In addition, the leaf network elements are interconnected to multiple spine network elements in a full mesh configuration, so that each of the leaf network elements can send data packets to the any of the spine network elements in one hop. Each of the leaf network elements can have high-speed uplink ports (e.g., 40 gigabits per second (Gbps) or 100 Gbps) connected to the spine network elements and lower speed downlink ports (e.g., 10 Gbps) connected to the servers in the server rack corresponding to that leaf network element.
A problem that can occur with this type of network architecture (or other types of multiply connected network architecture) if a network element or device misbehaves and causes a backup of the flow of traffic along a path that include this misbehaving node or device. In this problem, with a misbehaving network element or device along a path, data that is buffered for transmission in a queue along the path will not be transmitted. Instead, the queue starts to fill up and can eventually become full were no more data can be buffered in that queue. The device or network element can send pause messages to other devices or network elements that are sending data to the device or network element that has the filling queue due to the misbehaved network element or device. A pause message is a message sent to another device or network element indicating that other device or network element is not to send data to a device or network element that sent the pause message. This is further compounded is a network element that receives a pause message stops sending data and the queue for this network element fills up. Then, this network element will start sending pause message to other network element, where these network elements will than stop sending data. This can lead to a severe disruption in the network.